I have decided to get the AKG 701 headphones and have also been looking for a headphone amp. The CSP2 seems to fit the bill. What I have read about the sound looks promising. The unit also has a great advantage in being a preamp, so that it can double as the first step towards a later upgrade of the amplification and speakers, and doing that without putting limitations on what speakers to choose, unlike the couple of low-powered integrated amps/headphone amps which I also have been considering.

Now, the AKG 701s seem to demand careful partnering to bring their potential out. I wonder if owners of the AKG 701s and the CSP2 would agree with the following extracts from Headroom's description of these headphones, which could seem to contradict some other reports about these cans a bit, apparently from people with inadequate amplification:

"These cans deliver a dynamic and punchy sound, articulate and clear over the full audio spectrum. Bass lovers should appreciate the clean punch and tightly focused bottom-end control of these headphones. Classical and acoustic music fans will likewise love the fact that the dynamic control moves right on up the frequency range [...]. About the only thing that we can possibly say bad about these headphones is that those who like a very laid-back, mellow or heavy bass presentation might want to look elsewhere [...]."

"These cans deliver a dynamic and punchy sound, articulate and clear over the full audio spectrum. Bass lovers should appreciate the clean punch and tightly focused bottom-end control of these headphones. Classical and acoustic music fans will likewise love the fact that the dynamic control moves right on up the frequency range."

Ask 10 audiophiles who each prefer a different brand/model of headphone what they think of their headphones. Each one of them could say exactly what Headroom said. Use your own ears.

I can't comment on the CSP2 as a headphone amp yet, but it is a wonderful pre-amp. It is very transparent, has ultra low noise, and drives my decware amps very nicely. I do wish mine had and extra input in lieu of the mono output.

Thanks for replying. The CSP2 sure looks like an excellent preamp, with a "modern tube sound", and I'm also sure that the spatial properties of the AKG 701 headphones will be taken care of as well.

Actually, user responses to the AKG 701s vary quite a bit, and many find them reticent and something they choose when they want to "take a step back". Apparently, they need considerable juice to make all aspects of them come out, to give them body, presence, boogie and incredible dynamics. They are supposed to lean towards the amplication demands of the AKG 1000s, although not to that extreme.

This is my first post in the Decware Forums, but I've been following the various CSP2 and headphones threads for a while. I've had my CSP2 for about six weeks and I like it very much; it's an excellent preamp. I'm sure it's also a great headphone amp, but not for my AKG 701 (62 ohms) or Etymotic ER-4S (100 ohms) headphones. With either, I find it's impossible for me to get enough volume without distortion from impedence mismatching becoming a problem, and this occurs long before any danger of deafening sound levels. I know Steve designed the CSP2's circuit for the utmost fidelity--and 'phones 250 ohms or above--but I'm wondering if I could beg him to install some kind of high-low impedence switching option anyway. ??? There's definitely room for the switch! I don't know how many CSP2s are out in the world--I have #11--but is anyone using one successfully with AKG 701s? If so, I'd like to hear about it. Otherwise, Sennheiser HD 650, here I come, I guess.

Thanks very much for your two cents, SteveH. I agree with your comments about extension: The AKG 701s and the CSP2 definitely have this quality in common. But do you get enough volume without distortion for listening to music? I tried several sources, three digital--a Scott Nixon USBTD/iBook combo, an Ah! Toejb '99 cdp, and a 4th gen iPod--and one analog-- a fi Yph phono stage--and the result was always the same, distortion at an unsatisfyingly low volume, no matter what music I'm listening to: rock, jazz, or classical, vocal or instrumental, chamber, large group, or orchestral. I do not get this result when I use another headphone amp, such as the Emmeline SR-71. What's your secret?